Pulsed Arc Welding Current Regulation for Stability
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Solution Overview
Problem
Existing arc welding methods face challenges in achieving a high deposition rate while stabilizing the arc length and preventing spatter and short circuits, particularly when using pulsed current phases with varying arc resistances.
Innovation Solution
Regulating the welding current in the intermediate current phase based on the actual current and voltage values of the welding power source, ensuring a consistent pulsed current amplitude for targeted droplet detachment and stabilizing the arc length by adjusting the current setpoint dynamically in response to arc resistance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulsed welding current is used to achieve high deposition rate, then material transfer efficiency is improved, but arc length stability deteriorates due to varying arc resistance
Solution Approach 1:
The patent implements dynamic current regulation in the intermediate current phase based on real-time arc resistance feedback. The control unit continuously monitors arc resistance and dynamically adjusts the welding current amplitude to maintain stable arc length while preserving high deposition rate benefits from pulsed welding
Solution Approach 2:
The patent introduces a feedback control mechanism where the control unit monitors actual welding parameters (arc resistance, current, voltage) and uses this information to dynamically regulate the intermediate current phase. This closed-loop feedback ensures arc length stability while maintaining high productivity
2Productivity
If spray arc is used to increase material detachment rate, then deposition rate is improved, but spatter formation increases
Solution Approach 1:
The patent employs periodic pulsed current phases followed by intermediate current phases to control droplet detachment. This periodic action allows material to be detached in controlled single droplets rather than continuous spray, reducing spatter while maintaining high deposition rate through optimized pulse frequency and amplitude
Solution Approach 2:
The patent dynamically changes current amplitude parameters between basic current phase, pulsed current phase, and intermediate current phase. By optimizing these parameter transitions, the process achieves high material transfer efficiency while controlling droplet formation to minimize spatter
3Manufacturing precision
If pulsed current amplitude is increased for droplet detachment, then single droplet transfer is improved, but arc length control becomes difficult
Solution Approach 1:
The control unit uses real-time feedback from arc resistance monitoring to automatically adjust current parameters during the intermediate current phase. This feedback mechanism maintains precise single droplet detachment while compensating for arc length variations, making the process easier to control
Solution Approach 2:
The welding system performs self-regulation during the intermediate current phase by automatically adjusting current based on arc resistance. This self-service capability maintains precise droplet detachment and arc length control without requiring constant manual intervention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables a high deposition rate with reduced spatter and short circuits, maintaining a stable arc that is easy to handle, allowing for deep, finger-like penetration and strong connections between workpieces.
Implementation Method 1
an electric arc burns in a protective gas atmosphere between a welding torch that is continuously fed to a welding torch and a workpiece
Implementation Method 2
Due to the arc, the end of the welding electrode on the arc side is heated to such an extent that it liquefies
Implementation Method 3
The strong increase in the pulse current amplitude means that drops are detached from the liquefied end of the welding electrode due to the so-called pinch effect
Data Source
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AI summary
The light-arc welding process comprises burning an electrical arc between a fused welding electrode continuously fed to a welding torch and a workpiece in a protective gas atmosphere, passing a material melted by the welding electrode into a melting bath on the workpiece, supplying a pulsed welding current to the welding electrode by a welding current source (12), where the pulsed welding current has a basic current phase, a pulsed current phase and an intermediate current phase subsequent to the pulsed current phase, and regulating the welding current in the intermediate current phase. The light-arc welding process comprises burning an electrical arc between a fused welding electrode continuously fed to a welding torch and a workpiece in a protective gas atmosphere, passing a material melted by the welding electrode into a melting bath on the workpiece, supplying a pulsed welding current to the welding electrode by a welding current source (12), where the pulsed welding current has a basic current phase, a pulsed current phase and an intermediate current phase subsequent to the pulsed current phase, and regulating the welding current in the intermediate current phase on the basis of a current set-point value. The current set-point value is determined in dependent of the current actual value of the welding current and the voltage actual value of the output voltage of the welding current source. The current set-point value of the intermediate phase is determined under the consideration of the correction factors. The sum of the current actual value of the welding current and the voltage actual value of the output voltage of the welding current source is formed for the determination the current set-point value of the intermediate phase. The current actual value and the voltage actual value are measured with a correction factor. The current set-point value of the intermediate phase is formed from the sum of the current actual value and the deviations of the voltage actual value of the output voltage of the welding current source from a voltage fixed value and of the current actual value of the welding current from a current fixed value, where the deviations are measured with the correction factor. The welding current is cyclically regulated in the intermediate current phase, where an actual value of the welding current measured in the preceding regulating cycle, the set-point value of the welding current determined in the preceding regulating cycle and the actual value of the output voltage of the welding current source measured in the preceding regulating cycle are collected for the determination of the current set-point value in an actual regulating cycle, where the values are measured with the correction factor. A guiding parameter is assigned to several correction factors and the correction factors with the assignment are saved in a memory element. The correction factors associated to the guiding parameter are retrieved during the demand of a determined guiding parameter and are collected for determining the current set-point value of the intermediate current phase. The current set-point value of the intermediate current phase is limited to a minimum value and a maximum value. The duration of the intermediate current phase is limited to a minimum value. The intermediate current phase has duration of 5-10 ms. A representation actual value is detected, which characterizes the progression of the welding current in the intermediate current phase and is compared with a representation set-point value, where the current set-point value of the intermediate current phase, the current set-point of the basic current phase and/or the pulse frequency of the welding current are changed on the basis of the comparison of the representation actual value with the representation set-point value. The representation actual value is compared with maximum and minimum values of the current set-point value of the intermediate current phase, and is changed in dependent of the results of the comparison of the current set-point value of the basic current phase and/or the pulse frequency of the welding current. The current set-point value of the basic current phase and/or the pulse frequency of the welding current are regulated, where a predetermined set-point value of the basic current- and/or pulse frequency regulation or a gain factor of the basic current and/or pulse frequency regulation is changed in dependent of the deviation of the representation actual value from the representation set-point value. The gain factor is proportionally or integral-proportionally changed to the amount of the deviation of the representation actual value from the representation set-point value. The actual value of the welding current smoothed over the duration of the intermediate current phase is used as representation actual value in the intermediate current phase. An independent claim is included for a welding current source for performing a light-arc welding process.